Molecule-based system with coexisting conductivity and magnetism and without magnetic inorganic ions

An ion-radical salt, ${\left(\text{ESBN}\right)}_2{\text{ClO}}_4$, obtained from the electrochemical crystallization of an organic donor radical, ESBN, exhibited giant negative magnetoresistance ($-70\%$ at 2 K in 9 T) in spite of the absence of metal ions. Furthermore, it was found that the conductivity of ${\left(\text{ESBN}\right)}_2{\text{ClO}}_4$ was characterized by a distinct nonlinear temperature dependence and a nonlinear power law of $I\propto V^n$ $\left(n=12\right)$. We speculated that such correlated spin-dependent electron transportation is derived from the charge-ordered electronic structure and the strong intramolecular ferromagnetic coupling between $\pi$-conduction electrons and $\pi$-localized spins in the “spin-polarized donor.”